This invention relates to a one-piece load line pocket for a balloon, such as a hot air sport balloon or the like. The load line pocket is characterized by resisting tears from one panel to the next and facilitating easy stitching of adjacent balloon gores together. In addition, the load line pocket provides a strong, uniform structure within which to insert the balloon load lines.
Hot air sport balloons include a generally spherical balloon envelope having a downwardly directed mouth on its lower end. A carriage is mounted below the mouth of the envelope by load lines. The carriage supports the pilot and any passengers as well as a gas burner assembly which heats air and propels it through the mouth into the envelope.
Some balloons include an opening at the apex of the balloon. The apex opening is covered by circular valve panels which are controllable by the pilot to selectively cover and uncover the opening. In this way, controlled venting of the envelope is permitted.
Hot air balloon envelopes are typically formed of a plurality of four-sided fabric panels which are interconnected to form a number of vertical gores which extend from the mouth to the apex opening. The gores are joined together side by side to form the sphere-like structure. Conventional prior art balloons have gores which are connected together directly by means of a lap seam utilizing a two-thread locking stitch. This structure has been improved upon significantly by a prior development of the present applicant/assignee in patent application Ser. No. 258,615 entitled "Balloon Envelope." In the '615 application an inflatable balloon envelope is formed by a latticework of interconnected tapes including a plurality of vertical tapes which divide the envelope into several vertically disposed gores. A plurality of laterally directed tapes extend between the vertical tapes within each gore in such manner that the vertical tapes and laterally directed tapes collectively define a plurality of open areas covered by lightweight, air-impermeable sheet material. Each of the vertical tapes is composed of a pair of like tape components which have partially overlapping portions and adjacent non-overlapping portions. Laterally spaced-apart seams extend through the overlapping portions to interconnect the tape components and at the same time define a pocket between the two tape components within which the load line is freely extended. Thus, the load line pocket is formed by laterally spaced-apart seams. Furthermore, the tape components themselves are stitched to adjacent panels by stitching through the non-overlapping portions of the adjacent tape components.
Balloon panels are by necessity very lightweight and hence are succeptible to tearing, especially as a result of contact with ground objects during landing. One of the features of the invention described in the '615 application is the ability of the structure to prevent a tear in one fabric panel from continuing across a seam to an adjacent panel either within the same gore or to an adjacent gore. As described above, the load line pocket intermediate each gore is constructed by a series of parallel lines of stitching.
First, these rows of stitching are formed individually, meaning that a substantial amounts of time and labor are involved since each balloon gore is relatively long. Even a slight flaw in the row of stitching often requires that the entire row be pulled out and sewn again. This, of course, requires even more time and labor and can affect the strength of the tape components and the balloon fabric from which the panels are constructed.
Secondly, the load line pocket must be constructed with extreme care so that it will be of an exact and uniform volume and width since the load line must be positioned for free movement within the pocket. Therefore, there is a close tolerance within which the dimensions of the load line pocket must fall. A load line pocket which is constructed too small makes it difficult to pass the load line through the pocket, and at the restricted point, causes abrasion which over time can cause a safety-related defect in the balloon envelope.